Prosthetic heart valve with upper skirt

ABSTRACT

Apparatus for use at a native atrioventricular valve of a heart of a subject includes a prosthetic valve structure. The prosthetic valve structure comprises a valve ring, a leaflet frame, a plurality of prosthetic leaflets, and an upper skirt. The valve ring circumscribes a longitudinal axis of the prosthetic valve structure. The leaflet frame is disposed within the valve ring. The prosthetic leaflets are coupled to the leaflet frame, and are configured to facilitate upstream-to-downstream bloodflow longitudinally through the prosthetic valve structure. The upper skirt includes an annular skirt fabric, and an annular skirt frame coupled to the valve ring by the skirt fabric. The upper skirt extends radially outward and in an upstream direction from the valve ring. The upper skirt is configured to rest against an atrial portion of the native atrioventricular valve. Other embodiments are also described.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a Continuation of U.S. Ser. No. 16/388,038 toHaCohen, filed Apr. 18, 2019, and entitled “ROTATION-BASED ANCHORING OFAN IMPLANT,” which is a Continuation of U.S. Ser. No. 16/183,140 toHaCohen, filed Nov. 7, 2018, and entitled “FOLDING RING PROSTHETIC HEARTVALVE,” which published as U.S. 2019/0069998, and which is a Divisionalof U.S. Ser. No. 15/188,507 to HaCohen, filed Jun. 21, 2016, andentitled “FOLDING RING IMPLANT FOR HEART VALVE,” which published as U.S.2016/0296330 (now U.S. Pat. No. 10,231,831), and which is a Continuationof U.S. Ser. No. 14/522,987 to HaCohen, filed Oct. 24, 2014, andentitled “IMPLANT FOR ROTATION-BASED ANCHORING,” which published as U.S.2015/0045880 , and which is a Continuation of U.S. Ser. No. 12/961,721to HaCohen, filed Dec. 7, 2010, and entitled “ROTATION-BASED ANCHORINGOF AN IMPLANT,” which published as 2011/0137410 (now U.S. Pat. No.8,870,950), which claims the benefit of U.S. Provisional PatentApplication 61/283,819, entitled “FOLDABLE HINGED PROSTHETIC HEARTVALVE,” to Hacohen, filed Dec. 8, 2009, which is incorporated herein byreference.

FIELD OF EMBODIMENTS OF THE INVENTION

Embodiments of the present invention relates in general to valvereplacement. More specifically, embodiments of the present inventionrelate to replacement of an atrioventricular valve and prosthetic valvetherefor.

BACKGROUND

Ischemic heart disease causes regurgitation of a heart valve by thecombination of ischemic dysfunction of the papillary muscles, and thedilatation of the ventricle that is present in ischemic heart disease,with the subsequent displacement of the papillary muscles and thedilatation of the valve annulus.

Dilation of the annulus of the valve prevents the valve leaflets fromfully coapting when the valve is closed. Regurgitation of blood from theventricle into the atrium results in increased total stroke volume anddecreased cardiac output, and ultimate weakening of the ventriclesecondary to a volume overload and a pressure overload of the atrium.

SUMMARY OF EMBODIMENTS

In some applications of the present invention, a prosthetic heart valvestructure is provided that collapses and expands by means of one or morevalve pivot joints. The prosthetic valve structure is typicallydesignated for implantation in a native atrioventricular valve site of aheart of a patient, although for some applications, the prosthetic valvestructure is designated for implantation at the aortic or tricuspidvalve. The prosthetic valve structure comprises an annular ring portionthat is designated for placement adjacent to the ventricular surface ofthe native valve of the patient. This annular ring portion comprises thevalve pivot joints, which facilitate collapsing of the prosthetic valvestructure for transcatheter advancement of the valve toward the heart ofthe patient. Additionally, the annular portion of the prosthetic valvestructure is coupled to a plurality of anchors which are configured tograsp the native chordae tendineae of the heart of the patient. Theseanchors comprise generally curved prong structures which, in an expandedstate of the prosthetic valve structure, are aligned circumferentiallyalong the annular ring portion of the prosthetic valve structure(generally perpendicular to a radius of the annular ring portion). Oncethe annular ring portion is positioned adjacent to the ventricularsurface of the native mitral valve, the prosthetic valve structure isrotated, in order for the anchors to engage the native chordaetendineae. During the engaging, portions of the native chordae tendineaeare gathered between each anchor and a respective portion of the annularring. This engaging provides support to the prosthetic valve structureas it is positioned in and replaces the native valve. Additionally, theprosthetic valve structure comprises ventricular and atrial skirts whichprovide flush positioning of the prosthetic valve in the native valve.

There is therefore provided, in accordance with some applications of thepresent invention, apparatus for use with a prosthetic valve that isdesignated for implantation at a native heart valve of a patient,including:

a valve ring having a plurality of ring segments, each of the segmentsbeing hingedly coupled to at least one adjacent segment at a pivotjoint,

the valve ring being configured:

-   -   to be placed adjacent to a surface of the native heart valve,        the prosthetic valve having been coupled to the valve ring,    -   in an expanded state thereof, to define a ring, all of the pivot        joints being disposed in a plane that is perpendicular to a        longitudinal axis of the ring, and    -   to be foldable from the expanded state into a shape that has a        generally circular cross-section that defines and surrounds at        least in part a central lumen, by folding the segments with        respect to each other, at the pivot joints.

For some applications, the segments of the ring are configured to becomeat least partially twisted due to the ring being folded from theexpanded state.

For some applications, the prosthetic valve includes a trileaflet valve,and the ring has a number of ring segments that is a multiple of six.

For some applications, the ring has exactly six segments.

For some applications, the prosthetic valve includes a bileaflet valve,and the ring has a number of ring segments that is a multiple of four.

For some applications, the ring has exactly four segments.

There is further provided, in accordance with some applications of thepresent invention, a method for use with a prosthetic valve that isdesignated for implantation at a native heart valve of a patient,including:

placing in a vicinity a surface of the native heart valve, a valve ringthat is coupled to the valve, while the valve ring is in a folded statethereof,

-   -   the ring having a plurality of ring segments, each of the        segments being hingedly coupled to at least one adjacent segment        at a pivot joint,    -   in the folded state thereof, the ring having a shape that has a        generally circular cross-section that defines and surrounds at        least in part a central lumen;    -   expanding the ring such that all of the pivot joints become        disposed in a plane that is perpendicular to a longitudinal axis        of the ring, by applying a force to at least some of the pivot        joints; and    -   when the ring is in an expanded state thereof, positioning the        ring adjacent to a surface of the native valve.

For some applications, applying the force to some of the pivot jointsincludes pushing on pivot joints that are disposed on a proximal side ofthe ring, while the ring is in the folded state thereof.

For some applications, the native valve includes a native mitral valve,and positioning the ring adjacent to the surface of the valve includespositioning the ring adjacent to a ventricular surface of the nativemitral valve.

There is additionally provided, in accordance with some applications ofthe present invention, apparatus for use with a prosthetic valve that isdesignated for implantation at a native mitral valve of a patient,including:

an annular ring configured to be placed at a ventricular surface of thenative mitral valve, the prosthetic valve having been coupled to theannular ring; and

at least one anchor disposed circumferentially with respect to theannular ring so as to define a space between the anchor and the annularring.

For some applications, the anchor is configured to grasp a portion ofnative chordae tendineae of a heart of the patient by the annular ringbeing rotated.

For some applications, the annular ring is configured to be collapsible.

For some applications, the ring includes a plurality of ring segments,each of the segments being hingedly coupled to at least one adjacentsegment at a pivot joint, and the ring is configured to be collapsed byfolding the segments with respect to each other, at the pivot joints.

There is further provided, in accordance with some applications of thepresent invention, a method, including:

positioning an annular ring portion of a prosthetic valve structure at aventricular surface of a native heart valve of a patient; and

grasping a portion of native chordae tendineae of a heart of the patientby rotating the annular ring portion of the prosthetic valve structure.

In some applications of the present invention, grasping the portion ofthe native chordae tendineae includes facilitating placing the portionof the native chordae tendineae in a space between a segment of theannular ring portion and an anchor disposed circumferentially withrespect to the segment of the annular ring portion.

In some applications of the present invention, positioning the annularring portion includes:

transcatheterally advancing the prosthetic valve structure toward thenative valve of the patient in a collapsed state thereof; and

expanding the prosthetic valve structure from the collapsed state.

In some applications of the present invention, expanding the prostheticvalve structure includes pivoting a plurality of segments of the annularring portion at respective pivot joints that couple together adjacentsegments of the annular ring portion.

The present invention will be more fully understood from the followingdetailed description of embodiments thereof, taken together with thedrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an exploded view of a prostheticheart valve, in accordance with some applications of the presentinvention;

FIGS. 2A-B are schematic illustrations of the prosthetic heart valve ofFIG. 1 in an assembled, collapsed state, in accordance with someapplications of the present invention;

FIG. 3 is a schematic illustration of the prosthetic heart valve of FIG.1 in an assembled, expanded state, in accordance with some applicationsof the present invention; and

FIG. 4 is a schematic illustration of respective views of the prostheticheart valve of FIG. 1, while anchors of the valve are anchoring thevalve to chordae tendineae of a subject, in accordance with someapplications of the present invention.

The following figures, mutatis mutandis, originate from U.S. ProvisionalPatent Application 61/283,819 to HaCohen, which was incorporated byreference into the original specification of U.S. Ser. No. 12/961,721 toHaCohen:

FIG. 5 is a schematic illustration of an exploded view of a prostheticheart valve, in accordance with some applications of the presentinvention;

FIG. 6 is a schematic illustration of the prosthetic heart valve of FIG.5 in an assembled, expanded state, in accordance with some applicationsof the present invention; and

FIG. 7 is a schematic illustration of the prosthetic heart valve of FIG.5 in an assembled, collapsed state, in accordance with some applicationsof the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference is now made to FIGS. 1-4, which are schematic illustrations ofan expandable and collapsible prosthetic valve structure 20, inaccordance with some applications of the present invention. Theprosthetic valve structure is configured for implantation in andreplacement of a native atrioventricular valve of a patient. Typically,the prosthetic valve structure is configured for implantation in andreplacement of a native mitral valve of the patient.

The prosthetic valve structure comprises an annular valve ring 24, whichcomprises a plurality of curved metal segments 26 and a plurality ofpivot joints 30 which facilitate the collapsing and expanding of theprosthetic valve structure. The annular valve ring is typicallysurrounded by a valve ring fabric sleeve 34 comprising a braided mesh offabric, e.g., Dacron. This sleeve promotes fibrosis followingimplantation of the prosthetic valve structure in the native valve ofthe patient. The annular valve ring is coupled to a prosthetic valvethat includes a plurality of valve leaflets 44. The valve leaflets arecoupled to a flexible valve leaflet frame 40 (e.g., comprising nitinol,by way of illustration and not limitation), which is, in turn, coupledto a valve leaflet frame fabric 42. Typically, the valve leaflet framefabric (e.g., a fabric comprising Dacron) is coupled to (for example,sutured to) valve ring fabric sleeve 34.

For embodiments in which the prosthetic valve is designated to replacethe native mitral valve of the patient, the prosthetic valve comprisesthree artificial or tissue-based leaflets 44 a, 44 b, and 44 c (shown inFIG. 4), which are coupled to the inner perimeter of the annular valvering. For example, the leaflets may include pericardium, a polymer,and/or other materials, as would be obvious to one skilled in the art.

The annular valve ring portion of the prosthetic valve structure iscoupled: (1) at a first surface thereof to an upper skirt, whichcomprises an upper skirt fabric 38 coupled to a flexible upper skirtframe 36, and (2) at a second surface thereof to a lower skirt, whichcomprises a lower skirt fabric 48 coupled to a flexible lower skirtframe 46. Typically, the upper and lower frames comprise a flexiblematerial, e.g., nitinol by way of illustration and not limitation.Typically, when the prosthetic valve structure is implanted in theexpanded state, as shown in FIG. 4:

(a) the annular valve ring portion is configured to be disposed at aventricular surface of the native valve,

(b) the upper skirt is designated to rest against an atrial portion ofthe native mitral valve, and

(c) the lower skirt is designated to rest against a ventricular surfaceof the native valve and to push radially the native leaflets of thenative valve.

FIG. 1 shows components 22 of valve structure 20 in an exploded view.Each segment 26 of annular valve ring 24 is coupled at its respectiveends to respective ends of adjacent segments via a hinge. For example,as shown, the hinge may include a connecting element 28 that is insertedinto holes in the ends of the adjacent segments, such that the adjacentsegments form a pivot joint 30. The pivot joints of the ring portionenable the entire prosthetic valve structure to pivot into a collapsedstate, the collapsed state being shown in FIGS. 2A-B. Typically, thevalve comprises: (a) three “upper” valve pivot joints 30U (shown in FIG.2A) which are disposed at 120 degrees along the annular valve ring andare near the upper skirt frame 36, in the collapsed state of the valve,shown in FIG. 2A; and (b) three “lower” valve pivot joints 30L (shown inFIG. 2A) also disposed with a separation therebetween of 120 degrees,alternating with the upper valve pivot joints. The lower valve pivotjoints are near the lower skirt frame 46, in the collapsed state of thevalve as shown in FIG. 2A. The upper valve pivot joints are exposed at aproximal portion of the valve in the collapsed state of the valve (i.e.,adjacent to an upper skirt region of the prosthetic valve structure, asshown in FIG. 2A), such that a physician is able to push on the uppervalve pivot joints with a pushing tool, as described hereinbelow.Typically, when the ring is in its expanded state, all of the pivotjoints are disposed in a plane that is perpendicular to longitudinalaxis 10 of ring 24.

The pivot joints enable the prosthetic valve structure to collapse toform a shape having a generally circular cross-section that defines andsurrounds at least in part a central lumen 50, as shown in FIGS. 2A-B.Typically, the pivot joints enable the valve to assume an outer diameterof less than 10 mm, e.g., less than 6 mm (by way of illustration and notlimitation), in its collapsed state, as shown in FIG. 2A. Furthertypically, central lumen 50 (which is defined by ring 24 in itscollapsed state) has a cross-sectional length (e.g., diameter D, shownin FIG. 2B) of between 3 mm and 5 mm, the length being measured in aplane that is perpendicular to longitudinal axis 10 of the valve (shownin FIG. 1).

Typically, when used with a trileaflet valve, ring 24 includes sixsegments 26, such that there are a total of six pivot joints 30 (ofwhich three are upper pivot joints 30U, and three are lower pivot joints30L), and such that each of the leaflets is disposed between twoadjacent upper pivot joints 30U, or two adjacent lower pivot joints 30L.For some applications, the ring includes twelve (or another multiple ofsix) pivot joints, such that each of the leaflets of a trileaflet valveis disposed between two non-adjacent upper pivot joints 30U, or twonon-adjacent lower pivot joints 30L. For some applications, ring 24 isused with a bileaflet valve. For such applications, the ring may includefour, eight, or twelve segments 26, such that there are a correspondingnumber of pivot joints, and such that each of the leaflets is disposedbetween two of the upper pivot joints or two of the lower pivot joints.

Each of segments 26 of ring 24 is configured to become twisted when thering is folded, as shown in FIG. 2A. For some applications, due toshape-memory properties of the segments, the segments facilitate theexpansion of the ring, since the segments are pre-shaped in non-twistedshapes.

In the collapsed state of the valve, the valve leaflet frame, the valveleaflets, the upper skirt, and the lower skirt are also collapsed.Typically, the valve is configured such that the expansion of the ringcauses each of the aforementioned portions to become expandedautomatically.

In order to deploy prosthetic valve structure 20 inside the heart, thephysician pushes the upper pivot joints 30U distally, using a pushingtool. The pushing of the upper pivot joints enables annular valve ring24 to expand radially in order for the prosthetic valve structure toassume an expanded state, as shown in FIG. 3. Responsively to theexpanding of the prosthetic valve structure, valve leaflet frame 40,valve leaflets 44, upper skirt frame 36, and lower skirt frame 46 alsoexpand from their respective collapsed states.

For some applications, annular valve ring 24 is coupled to a pluralityof generally curved, prong-shaped anchors 32, for example, four to eightanchors, e.g., six anchors, as shown by way of illustration and notlimitation in FIG. 1. In the expanded state of valve structure 20, asshown in FIG. 3, the anchors are disposed circumferentially and inconcentric alignment with the annular valve ring. As shown in FIG. 3,the anchors project from the annular valve ring through the valve ringfabric sleeve 34. As the prosthetic valve structure transitions to acollapsed state, as shown in FIG. 2A, the anchors remain alongsiderespective segments of the annular valve ring to which each anchor isadjacently disposed in the expanded state of the prosthetic valvestructure.

During implantation of prosthetic valve structure 20, a lower portion ofthe prosthetic valve structure is first advanced toward the ventricularsurface of the native valve. Once the distal end of the catheter ispositioned in the ventricle of the patient, the physician pushesdistally on the upper valve pivot joints 30 in order to (1) exposeannular valve ring portion 24 and the lower skirt frame 46 and lowerskirt fabric 48 from within the catheter, and (2) in conjunction, expandthe annular valve ring. As the annular valve ring expands, lower skirtframe 46, valve leaflet frame 40, and valve leaflets 44 passively (i.e.,automatically) expand. As the physician expands the annular valve ring,each of the anchors remain disposed circumferentially with respect tothe segment of the annular valve ring to which the anchor is adjacentlydisposed (as shown in FIG. 3). In such a manner, a space is createdbetween each anchor and the respective segments of the annular valvering to which each anchor is adjacently disposed.

By pulling proximally on the catheter and the tool coupled to prostheticvalve structure 20 disposed therein, the annular valve ring ispositioned adjacent to a ventricular surface of the native valve. Oncethe valve ring portion is positioned adjacent to the ventricularsurface, the physician rotates annular valve ring 24 (e.g., by rotating30 degrees a tool coupled thereto) about an axis that runs between thenative valve from the atrium to the ventricle (which during implantationof the valve, is typically approximately aligned with longitudinal axis10 of the valve). During this rotation, portions of native chordaetendineae 60 are grasped and placed between each anchor and therespective segment of the annular valve ring to which the anchor isadjacently disposed, as shown in FIG. 4. This grasping of the leafletsprovides supplemental support to the prosthetic valve during andfollowing implantation thereof. Alternatively or additionally, supportis provided to the prosthetic valve by the upper and lower skirts,and/or by ring 24.

In conjunction with the grasping of the chordae tendineae, theprosthetic valve is secured in place. The physician then pulls thecatheter proximally in order to expose upper skirt frame 36 and upperskirt fabric 38 from within the catheter. The skirt then expands overthe atrial surface of the native valve in order to create a flushcoupling between the prosthetic valve and the native valve.

The following description, mutatis mutandis, originates from U.S.Provisional Patent Application 61/283,819 to HaCohen, which wasincorporated by reference into the original specification of U.S. Ser.No. 12/961,721 to HaCohen:

Reference is now made to FIGS. 5-7 which are schematic illustrations ofan expandable and collapsible prosthetic valve 100, in accordance withsome applications of the present invention. The prosthetic valve isconfigured for implantation in and replacement of a nativeatrioventricular valve of a patient. Typically, the prosthetic valve isconfigured for implantation in and replacement of a native mitral valveof the patient. The prosthetic valve comprises an annular valve ring 110(as shown in the exploded view of FIG. 5), which comprises a pluralityof curved metal segments 112 and a plurality of pivot joints 114 whichfacilitate the collapsing and expanding of the prosthetic valve. Theannular valve ring 110 is typically surrounded by a valve ring fabricsleeve 116 comprising a braided mesh of fabric, e.g., Dacron. Thissleeve promotes fibrosis following implantation of the prosthetic valvein the native valve of the patient. The annular valve ring 110 iscoupled to a plurality of valve leaflets 120. The valve leaflets arecoupled to a flexible valve leaflet frame 122 (e.g., comprising nitinolby way of illustration and not limitation), which is, in turn, coupledto a valve leaflet frame fabric 124. Typically, the valve leaflet framefabric (e.g., a fabric comprising Dacron) is coupled to (for example,sutured to) the valve ring fabric sleeve.

For embodiments in which the prosthetic valve is designated to replacethe native mitral valve of the patient, the prosthetic valve comprisesthree artificial or tissue-based leaflets 120, as shown, which arecoupled to the inner perimeter of the annular valve ring. It is to benoted that although these leaflets are shown by way of illustration andnot limitation, as being a product of Neovasc Medical Ltd., the leafletsmay comprise any other leaflets known in the art.

The annular valve ring portion 110 of the prosthetic valve is coupled:(1) at a first surface thereof to an upper skirt 140, which comprises anupper skirt fabric 144 coupled to a flexible upper skirt frame 142, and(2) at a second surface thereof to a lower skirt 130, which comprises alower skirt fabric 134 coupled to a flexible lower skirt frame 132.Typically, the upper and lower frames comprise a flexible material,e.g., nitinol by way of illustration and not limitation. Typically, whenthe prosthetic valve is implanted in the expanded state, as shown inFIG. 6:

(a) the annular valve ring portion is configured to be disposed at aventricular surface of the native valve,

(b) the upper skirt is designated to rest against an atrial portion ofthe native mitral valve, and

(c) the lower skirt is designated to rest against a ventricular surfaceof the native valve and to push radially the native leaflets of thenative valve.

FIG. 5 shows the components of the valve in an exploded view. Eachsegment 112 of the annular valve ring is coupled at its respective endsto respective ends of adjacent segments via a hinge, or a valve pivotjoint 114. The pivot joints of the ring portion enable the entireprosthetic valve to pivot into a collapsed state, as shown in FIG. 7.Typically, the valve comprises: (a) three “upper” valve pivot jointswhich are disposed at 120 degrees along the annular valve ring and arenear the upper skirt frame, as shown in FIG. 7; and (b) three “lower”valve pivot joints also disposed with a separation therebetween of 120degrees, alternating with the upper valve pivot joints. The lower valvepivot joints are near the lower skirt frame, as shown in FIG. 7). Theupper valve pivot joints are exposed at a proximal portion of the valvein a collapsed state (i.e., adjacent to an upper skirt region of theprosthetic valve, as shown in FIG. 7). The pivot joints enable theprosthetic valve to assume a diameter of 6 mm (by way of illustrationand not limitation) in its collapsed state, as shown in FIG. 7. In thecollapsed state, the valve leaflet frame, the valve leaflets, the upperskirt, and the lower skirt are also collapsed.

In order to deploy the prosthetic valve inside the heart, the physiciandistally pushes on the upper pivot joints using a pushing tool. Thepushing of the upper pivot joints enables the annular valve ring toexpand radially in order for the prosthetic valve to assume an expandedstate, as shown in FIG. 6. Responsively to the expanding of theprosthetic valve, the valve leaflet frame, the valve leaflets, the upperskirt, and the lower skirt also expand from their respective collapsedstates.

The annular valve ring is coupled to a plurality of generally curved,prong-shaped anchors 150, e.g., 6 as shown by way of illustration andnot limitation in FIG. 5.

In an expanded state, as shown in FIG. 6, the anchors are disposedcircumferentially and in concentric alignment with the annular valvering. As shown in FIG. 6, the anchors project from the annular valvering through the valve ring fabric sleeve. As the prosthetic valvetransitions to a collapsed state, as shown in FIG. 7, the anchors remainalongside respective segments of the annular valve ring to which eachanchor is adjacently disposed in the expanded state of the prostheticvalve.

During implantation of the prosthetic valve, a lower portion of theprosthetic valve is first advanced toward the ventricular surface of thenative valve. Once the distal end of the catheter is positioned in theventricle of the patient, the physician pushes distally on the uppervalve pivot joints in order to (1) expose the annular valve ring portionand the lower skirt from within the catheter, and (2) in conjunction,expand the annular valve ring. As the annular valve ring expands, thelower skirt, the valve leaflet frame, and the valve leaflets passivelyexpand. As the physician expands the annular valve ring, each of theanchors remain disposed circumferentially with respect to the segment ofthe annular valve ring to which the anchor is adjacently disposed (asshown in FIG. 6). In such a manner a space is created between eachanchor and the respective segments of the annular valve ring to whicheach anchor is adjacently disposed.

By pulling proximally on the catheter and the tool coupled to theprosthetic valve disposed therein, the annular valve ring is positionedadjacent to a ventricular surface of the native valve. Once the valvering portion is positioned adjacent to the ventricular surface, thephysician rotates the annular valve ring (e.g., by rotating 30 degrees atool coupled thereto) about an axis that runs between the native valvefrom the atrium to the ventricle. During this rotation, portions of thenative chordeae tendineae are grasped and placed between each anchor andthe respective segment of the annular valve ring to which the anchor isadjacently disposed. This grasping of the leaflets provides supplementalsupport to the prosthetic valve during and following implantationthereof.

In conjunction with the grasping of the chordeae tendineae, theprosthetic valve is secured in place. The physician then pulls thecatheter proximally in order to expose the upper skirt from within thecatheter. The skirt then expands over the atrial surface of the nativevalve in order to create a flush coupling between the prosthetic valveand the native valve.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather, the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove, as well as variations and modifications thereofthat are not in the prior art, which would occur to persons skilled inthe art upon reading the foregoing description.

The invention claimed is:
 1. Apparatus for use at a native atrioventricular valve of a heart of a subject, the apparatus comprising a prosthetic valve structure that comprises: a valve ring that circumscribes a longitudinal axis of the prosthetic valve structure; a plurality of prong-shaped anchors distributed around the valve ring, each of the anchors projecting from the valve ring; a leaflet frame, disposed within the valve ring; a plurality of prosthetic leaflets, coupled to the leaflet frame, and configured to facilitate upstream-to-downstream bloodflow longitudinally through the prosthetic valve structure; and an upper skirt, (i) comprising: an annular skirt fabric; and an annular skirt frame coupled to the valve ring by the skirt fabric, (ii) extending, radially outward and in an upstream direction, from the valve ring, and (iii) configured to rest against an atrial portion of the native atrioventricular valve.
 2. The apparatus according to claim 1, wherein an upstream portion of the leaflet frame is disposed within the valve ring.
 3. The apparatus according to claim 2, wherein an upstream end of the leaflet frame is disposed within the valve ring.
 4. The apparatus according to claim 2, wherein a downstream portion of the leaflet frame extends out of the valve ring.
 5. The apparatus according to claim 4, wherein each of the leaflets is disposed within, and secured to, the downstream portion of the leaflet frame.
 6. The apparatus according to claim 5, wherein each of the leaflets is also disposed within, and secured to, the upstream portion of the leaflet frame.
 7. The apparatus according to claim 5, wherein: the downstream portion of the leaflet frame comprises a plurality of posts, and at each post of the plurality of posts, a part of a first leaflet of the plurality of leaflets converges with a part of a second leaflet of the plurality of leaflets, the part of the first leaflet and the part of the second leaflet are secured to the post.
 8. The apparatus according to claim 4, wherein all of the anchors are disposed entirely upstream of the downstream portion of the leaflet frame.
 9. The apparatus according to claim 1, further comprising a fabric sleeve attached to the valve ring.
 10. The apparatus according to claim 9, further comprising a leaflet frame fabric that is coupled to the leaflet frame, wherein the leaflet frame fabric is sutured to the fabric sleeve.
 11. The apparatus according to claim 1, wherein all of the anchors are entirely disposed downstream of the upper skirt.
 12. The apparatus according to claim 1, wherein each of the anchors projects from the valve ring radially outward and alongside the valve ring.
 13. The apparatus according to claim 1, wherein each of the anchors projects from the valve ring, defining a space between the anchor and the valve ring.
 14. The apparatus according to claim 1, wherein: the valve ring comprises a plurality of metal segments joined at a respective plurality of joints, the joints facilitating (i) collapsing of the prosthetic valve structure into a collapsed state for transcatheter delivery to the heart, and (ii) expanding of the prosthetic valve structure into a deployed state within the heart, and each of the anchors projects from a respective one of the plurality of joints.
 15. The apparatus according to claim 14, wherein: at each of the plurality of joints from which a respective anchor of the plurality of anchors projects, a first metal segment of the plurality of segments is joined to a second metal segment of the plurality of segments, and the respective anchor is shorter than the first metal segment and is shorter than the second metal segment.
 16. The apparatus according to claim 14, wherein, for each metal segment of the plurality of metal segments: a first end of the metal segment is joined at a first joint from which a first anchor of the plurality of anchors projects, a second end of the metal segment is joined at a second joint from which a second anchor of the plurality of anchors projects.
 17. The apparatus according to claim 14, wherein at each of the plurality of joints from which a respective anchor of the plurality of anchors projects, the respective anchor projects from the respective joint and generally toward another anchor of the plurality of anchors.
 18. The apparatus according to claim 14, wherein, in the collapsed state: the metal segments are arranged in a circumferential ring that defines a series of peaks and troughs, thereby defining (i) joints that are disposed at the peaks as upper-joints, and (ii) joints that are disposed at the troughs as lower-joints, at least one of the anchors projects from an upper-joint, and at least one of the anchors projects from a lower-joint.
 19. The apparatus according to claim 1, wherein the skirt frame comprises an elongate element that follows a closed wavy path that is (i) circumferentially around the longitudinal axis, and (ii) longitudinally separated from the valve ring.
 20. The apparatus according to claim 19, wherein the elongate element is disposed radially outward from the valve ring.
 21. The apparatus according to claim 19, wherein the prosthetic valve structure further comprises an additional elongate element that follows a closed wavy path that is (i) circumferentially around the longitudinal axis, and (ii) longitudinally separated from the valve ring.
 22. The apparatus according to claim 19, wherein: the elongate element is a first elongate element, the closed wavy path is a first closed wavy path, and defines alternating first-path crests and first-path dips, the first-path crests being further from the longitudinal axis than the first-path dips, the prosthetic valve structure further comprises a second elongate element that follows a second closed wavy path circumferentially around the longitudinal axis, the second closed wavy path defining alternating second-path crests and second-path dips, the second-path crests being further from the longitudinal axis than the second-path dips, and the alternating of the second closed wavy path is out of phase with the alternating of the first closed wavy path.
 23. The apparatus according to claim 19, wherein the wavy path has a wavelength, and wherein the prosthetic valve structure is collapsible into a collapsed state for transcatheter delivery to the heart, collapsing of the prosthetic valve structure into the collapsed state reducing the wavelength of the wavy path.
 24. The apparatus according to claim 1, wherein the prosthetic valve structure is collapsible into a collapsed state for transcatheter delivery to the heart.
 25. The apparatus according to claim 1, wherein the skirt frame comprises Nitinol.
 26. Apparatus for use at a native atrioventricular valve of a heart of a subject, the apparatus comprising a prosthetic valve structure that comprises: a valve ring that circumscribes a longitudinal axis of the prosthetic valve structure; a leaflet frame, disposed within the valve ring; a plurality of prosthetic leaflets, coupled to the leaflet frame, and configured to facilitate upstream-to-downstream bloodflow longitudinally through the prosthetic valve structure; and an upper skirt, (i) comprising: an annular skirt fabric; and an annular skirt frame coupled to the valve ring by the skirt fabric, and comprising an elongate element that follows a closed wavy path that is (i) circumferentially around the longitudinal axis, and (ii) longitudinally separated from the valve ring, (ii) extending, radially outward and in an upstream direction, from the valve ring, and (iii) configured to rest against an atrial portion of the native atrioventricular valve.
 27. The apparatus according to claim 26, wherein an upstream portion of the leaflet frame is disposed within the valve ring.
 28. The apparatus according to claim 27, wherein an upstream end of the leaflet frame is disposed within the valve ring.
 29. The apparatus according to claim 27, wherein a downstream portion of the leaflet frame extends out of the valve ring.
 30. The apparatus according to claim 29, wherein each of the leaflets is disposed within, and secured to, the downstream portion of the leaflet frame.
 31. The apparatus according to claim 30, wherein each of the leaflets is also disposed within, and secured to, the upstream portion of the leaflet frame.
 32. The apparatus according to claim 30, wherein: the downstream portion of the leaflet frame comprises a plurality of posts, at each post of the plurality of posts, a part of a first leaflet of the plurality of leaflets converges with a part of a second leaflet of the plurality of leaflets, and the part of the first leaflet and the part of the second leaflet are secured to the post.
 33. The apparatus according to claim 29, further comprising a plurality of prong-shaped anchors distributed around the valve ring, each of the anchors projecting from the valve ring, and all of the anchors being disposed entirely upstream of the downstream portion of the leaflet frame.
 34. The apparatus according to claim 26, further comprising a fabric sleeve attached to the valve ring.
 35. The apparatus according to claim 34, further comprising a leaflet frame fabric that is coupled to the leaflet frame, wherein the leaflet frame fabric is sutured to the fabric sleeve.
 36. The apparatus according to claim 26, further comprising a plurality of prong-shaped anchors distributed around the valve ring, wherein each of the anchors projects from the valve ring, and all of the anchors are entirely disposed downstream of the upper skirt.
 37. The apparatus according to claim 26, further comprising a plurality of prong-shaped anchors distributed around the valve ring, wherein each of the anchors projects from the valve ring radially outward and alongside the valve ring.
 38. The apparatus according to claim 26, further comprising a plurality of prong-shaped anchors distributed around the valve ring, wherein each of the anchors projects from the valve ring, defining a space between the anchor and the valve ring.
 39. The apparatus according to claim 26, further comprising a plurality of prong-shaped anchors distributed around the valve ring, wherein: the valve ring comprises a plurality of metal segments joined at a respective plurality of joints, the joints facilitating (i) collapsing of the prosthetic valve structure into a collapsed state for transcatheter delivery to the heart, and (ii) expanding of the prosthetic valve structure into a deployed state within the heart, and each of the anchors projects from a respective one of the plurality of joints.
 40. The apparatus according to claim 39, wherein: at each of the plurality of joints from which a respective anchor of the plurality of anchors projects, a first metal segment of the plurality of segments is joined to a second metal segment of the plurality of segments, and the respective anchor is shorter than the first metal segment and is shorter than the second metal segment.
 41. The apparatus according to claim 39, wherein, for each metal segment of the plurality of metal segments: a first end of the metal segment is joined at a first joint from which a first anchor of the plurality of anchors projects, and a second end of the metal segment is joined at a second joint from which a second anchor of the plurality of anchors projects.
 42. The apparatus according to claim 39, wherein at each of the plurality of joints from which a respective anchor of the plurality of anchors projects, the respective anchor projects from the respective joint and generally toward another anchor of the plurality of anchors.
 43. The apparatus according to claim 39, wherein, in the collapsed state: the metal segments are arranged in a circumferential ring that defines a series of peaks and troughs, thereby defining (i) joints that are disposed at the peaks as upper-joints, and (ii) joints that are disposed at the troughs as lower-joints, at least one of the anchors projects from an upper-joint, and at least one of the anchors projects from a lower-joint.
 44. The apparatus according to claim 26, wherein the elongate element is disposed radially outward from the valve ring.
 45. The apparatus according to claim 26, wherein the prosthetic valve structure further comprises an additional elongate element that follows a closed wavy path that is (i) circumferentially around the longitudinal axis, and (ii) longitudinally separated from the valve ring.
 46. The apparatus according to claim 26, wherein: the elongate element is a first elongate element, the closed wavy path is a first closed wavy path, and defines alternating first-path crests and first-path dips, the first-path crests being further from the longitudinal axis than the first-path dips, the prosthetic valve structure further comprises a second elongate element that follows a second closed wavy path circumferentially around the longitudinal axis, the second closed wavy path defining alternating second-path crests and second-path dips, the second-path crests being further from the longitudinal axis than the second-path dips, and the alternating of the second closed wavy path is out of phase with the alternating of the first closed wavy path.
 47. The apparatus according to claim 26, wherein the wavy path has a wavelength, and wherein the prosthetic valve structure is collapsible into a collapsed state for transcatheter delivery to the heart, collapsing of the prosthetic valve structure into the collapsed state reducing the wavelength of the wavy path.
 48. The apparatus according to claim 26, wherein the prosthetic valve structure is collapsible into a collapsed state for transcatheter delivery to the heart.
 49. The apparatus according to claim 26, wherein the skirt frame comprises Nitinol. 